Double-walled flexible dispenser sump connection system

ABSTRACT

A double-walled flexible dispenser sump connection system prevents fuel leaks into a dispenser sump located below a fuel dispenser. An inner flexible connector and an outer flexible connector are configured such that the dispenser sump connection system may be installed on newly constructed fuel delivery systems or be retrofitted onto existing fuel delivery systems in order to bring them into compliance with recently environmental regulations.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation application of U.S. patentapplication Ser. No. 11/679,618 filed Feb. 27, 2007, which is acontinuation patent application of U.S. patent application Ser. No.11/061,388 filed Feb. 18, 2005, currently pending, the entire contentsof which are incorporated herein by reference.

TECHNICAL FIELD

This invention relates generally to fuel dispenser sumps used in gasstations and in similar applications, and more particularly to adouble-walled flexible dispenser sump connection system that provides asafeguard against leaks from dispenser sumps located beneath thegasoline dispensers.

BACKGROUND AND SUMMARY OF THE INVENTION

State environmental and energy agencies require strict compliance withlaws and regulations regarding fuel storage and conveyance, inparticular regarding containment of fuel within the pipes and othercomponents beneath the ground surface at gas stations. Piping systemsfor conveying the fuel between the underground tanks and dispensers mustbe pressurized and vacuum sealed to detect and contain leaks therein.

Referring to FIG. 1, there is shown a common dispenser sump connectionsystem 10 below a dispenser 12 at a gas station. Fuel is conveyed from atank 14 through a primary inner pipe 16, traditionally two inches indiameter, into a dispenser sump 18 below the fuel dispenser 12. Onceinside the dispenser sump 18 the inner pipe 16 continues through anelbow joint 20 to a connecting inner pipe 22, which couples to a shearvalve 24 located at the bottom of the dispenser 12. The shear valve 24prevents fuel spills or leaks in the event that the dispenser 12 isdisplaced from the dispenser sump 18.

A secondary outer pipe 26, traditionally three inches in diameter,encloses the inner pipe 16 from the tank 14 to the dispenser sump 18.The outer pipe 26 prevents fuel from entering into and contaminating thegroundsoil and/or the atmosphere. The interstitial space between theouter pipe 26 and the inner pipe 16 is either pressurized or vacuumsealed to provide additional protection against leaks.

Although the outer pipe 26 contains any leaks between the tank 12 andthe dispenser sump 18, the outer pipe 26 terminates into a boot at thedispenser sump 18, leaving the inner pipe 16 is exposed inside thedispenser sump 18. Therefore, there are no safeguards to detect orcontain leaks that occur inside the dispenser sump 18, which can resultin leaks into the groundsoil surrounding the dispenser sump and/or intothe atmosphere. Recently, regulations have been passed in several statessuch as California which require safeguards be installed to preventleaks from dispenser sumps. Currently the approved safeguards requireretrofitting the existing dispenser sump 18 with the equivalent of anouter sump around the dispenser sump within the space between the outerand inner sump being either pressurized or vacuum sealed, or replacingthe existing dispenser sump with a double-walled pressurized sump. Thecost to install the outer sump or replace the existing sump costsapproximately $2,000 minimum per dispenser. Considering that most gasstations have multiple dispensers, the cost to retrofit the existingsumps to bring them into compliance can be substantial.

The present invention comprises a dispenser sump connection system whichovercomes the foregoing and other difficulties which have long sincecharacterized the prior art. In accordance with the broader aspects ofthe invention, an outer and inner flexible connector system providesprotection against fuel leakage from the dispenser sump. The innerflexible connector connects the primary inner pipe to the shear valve.The outer flexible connector completely encloses the inner flexibleconnector from the sump wall to the shear valve. The interstitial spacebetween the outer flexible connector and the inner flexible connector ispressurized and/or be vacuum sealed thereby preventing any fuel leakageinto the dispenser sump.

The outer and inner flexible connector system can be retrofitted insideexisting dispenser sumps at a minimal cost per dispenser. The presentinvention provides the high level of protection against leakage requiredby state environmental agencies and eliminates the need for installingan outer sump or retrofitting with a double-walled sump.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the invention may be had by referenceto the following Detailed Description when taken in conjunction with theaccompanying Drawings, wherein:

FIG. 1 is a sectional view illustrating a prior art fuel delivery anddispenser sump connection system;

FIG. 2 is a sectional view of the double-walled flexible dispenser sumpconnection system of the present invention;

FIG. 3 is an exploded perspective view of the dispenser sump connectionsystem shown in FIG. 2; and

FIG. 4 is a sectional view of the dispenser sump connection system shownin FIG. 2.

DETAILED DESCRIPTION

Referring now to the Drawings, and particularly to FIGS. 2, 3, and 4thereof, there is shown the dispenser sump connection system 30 of thepresent invention. An inner flexible connector 32 is connected to theinner pipe 16 for completing the conveyance of fuel to the dispenser 12.An outer flexible connector 34 is installed over and completely enclosesthe inner flexible connector 32. The lower end of the outer flexibleconnector 34 is connected in fluid communication with the outer pipe 26.The upper end of the outer flexible connector 34 is connected to theshear valve 24 thereby completing the containment of any leaks fromeither the inner pipe 16 and the inner flexible connector 32. Theinterstitial space between the outer flexible connector 34 and the innerflexible connector 32 is either pressurized or vacuum sealed therebypreventing any fuel leakage into the dispenser sump 18. The flexibleconnectors 32 and 34 used in conjunction with the present invention aredescribed in detail in U.S. Pat. Nos. 7,140,648; 6,922,893; and7,063,358.

In the embodiment shown in FIGS. 2 through 4, the inner flexibleconnector 32 couples to the inner pipe 16 through an elbow joint 36comprising an inner elbow joint 38 secured to the distal end of theinner pipe 16 and an outer containment clamshell 40, which glues overthe inner elbow joint 38 to contain any leaks that may occur therefrom.The dispenser sump connection system 30 of the present invention may bealso be secured directly to the inner and outer pipes 16 and 26, or byother connection means known to those skilled in the art and suitablefor use in fuel and hazardous material delivery systems.

FIG. 3 is an exploded view and FIG. 4 is a sectional view of thedispenser sump connection system 30. The inner flexible connector 32threadedly secures into the inner elbow joint 38, thereby completing theconnection of the inner flexible connector 32 to the inner pipe 16. Thetop of the inner flexible connector 32 has male threads for threadedlysecuring the inner flexible connector 32 into the shear valve 24. Theouter flexible connector 34 installs over the inner flexible connector32 and is connected to the elbow joint 36 by a lower connection ring 42,which extends around the end of the inner elbow joint 38. The outercontainment clamshell 40 when glued over the inner elbow joint 38 coversand thereby contains the connection of the lower connection ring 42 tothe inner elbow joint 38.

The lower end of the outer flexible connector 34 is secured to the lowerconnection ring 42 by a first hinged circular clamp 44 having a threadedlocking mechanism 46. A gasket 48 is mounted between the outer flexibleconnector 34 and lower connection ring 42. Wedge shaped surfaces on theouter flexible connector 34 and on the lower connection ring 42 andcorresponding shapes on the inner surfaces of the circular clamp 44,combined with the gasket 48, cause the outer flexible connector 34 andthe lower connection ring 42 to form a compression seal as the threadedlocking mechanism 46 is tightened.

The upper end of the outer flexible connector 34 is connected to theshear valve 24 by an upper connection ring 50. The outer flexibleconnector 34 is secured to the upper connection ring 50 by a secondhinged circular clamp 44 having a threaded locking mechanism 46. Agasket 48 is positioned between the outer flexible connector 34 andupper connection ring 50. Wedge shaped surfaces on the outer flexibleconnector 34 and on the upper connection ring 50 and correspondingshapes on the inner surfaces of the circular clamp 44, combined with thegasket 48, cause the outer flexible connector 34 and the upperconnection ring 50 to form a compression seal as the threaded lockingmechanism 46 is tightened. The upper connection ring 50 comprises femalethreads for threadedly securing an outer housing 52 of the shear valve24 thereinto.

Near the upper end of the outer flexible connector 34 is an orifice 54which facilitates either vacuum sealing or pressurization of theinterstitial space between the inner flexible connector 32 and the outerflexible connector 34. The lower connection ring 42, the upperconnection ring 50, and the hinged circular clamps 44 may be formed fromstainless steel, bronze, brass, monel, other metals, various polymericmaterials, and other materials that will not be adversely affected bythe fluid that will flow through the inner and outer flexible connectors32 and 34. The inner elbow joint 38 and the outer elbow joint 40 arecommercially available parts used in conjunction with fuel deliverysystems and other hazardous material delivery systems.

Although preferred embodiments of the invention have been illustrated inthe accompanying Drawings and described in the foregoing DetailedDescription, it will be understood that the invention is not limited tothe embodiments disclosed, but is capable of numerous rearrangements,modifications, and substitutions of parts and elements without departingfrom the spirit of the invention.

1. A fuel supply system comprising: a dispenser pump having a shearvalve at the bottom thereof for directing fuel into the dispenser pump;a dispenser sump located directly below the dispenser pump; a fuel tank;a piping system for conveying fuel from the fuel tank into the dispensersump; the piping system comprising an inner pipe for conveying fuel andan outer pipe surrounding the inner pipe for containment of leakstherefrom; an inner flexible connector extending through the dispensersump and coupled between the end of the inner pipe and the shear valvefor completing the conveyance of fuel into the dispenser pump; an outerflexible connector extending through the dispenser sump and coupledbetween the end of the outer pipe and the shear valve for enclosing theinner flexible connector and containing any fuel leakage therefrom; andmeans for continuously maintaining a predetermined pressure selectedfrom the group consisting of a predetermined positive pressure and avacuum seal within the interstitial space between the inner flexibleconnector and the outer flexible connector.
 2. The dispenser sumpconnection system of claim 1 wherein pressure maintaining means includesan orifice located at the upper end of the outer flexible connector. 3.The dispenser sump connection system of claim 2 wherein the innerflexible connector is threadedly secured to an inner elbow jointfastened to the distal end of the inner pipe and an outer containmentclamshell which is secured around the inner elbow joint.
 4. Thedispenser sump connection system of claim 3 wherein the inner flexibleconnector is threadedly secured to the shear valve.
 5. The dispensersump connection system of claim 4 further comprising: a first connectionring for coupling the outer flexible connector over the distal end ofthe inner pipe; a gasket seated between the first connection ring andthe outer flexible connector for facilitating a pressure seal; and aclamping ring having a threaded locking device for securing andcompressing the outer flexible connector and the first connection ringtogether.
 6. The dispenser sump connection system of claim 5 furthercomprising: a second connection ring for coupling the outer flexibleconnector to an outer housing of the shear valve; a gasket seatedbetween the second connection ring and the outer flexible connector forfacilitating a pressure seal; and a clamping ring having a threadedlocking device for securing and compressing the outer flexible connectorand the outer housing of the shear valve together.